This invention relates to aqueous compositions containing haloalkynyl microbicide in the presence of metal ions. In particular, the invention is directed to stabilized compositions of halopropargyl microbicides where the metal ions are provided in the form of chelated metal ion. Typically the aqueous compositions contain additional microbicidal compounds, such as 3-isothiazolones, and are useful in various end use applications, such as in the preservation of paints against contamination by microorganisms.
Various types of coatings are used to protect substrates, particularly wood, against both physical and microbial degradation. These coatings, typically in the form of paints, lacquers and varnishes, function as carriers for microbicidal agents and also provide a protective barrier against the environment. Of particular use are aqueous-based coatings, such as latex paints.
A well-known class of microbicides used in coating compositions are those based on haloalkynyl compounds, in particular halopropargyl compounds, and especially compounds containing an iodopropargyl group, such as 3-iodo-2-propynylbutylcarbamate (IPBC). Haloalkynyl compounds, including halo-propargyl carbamates, are formulated with a variety of other ingredients in both aqueous and organic solvent mixtures to form coating materials. Often additional antimicrobial agents are included in the formulations to enhance the overall efficacy of the microbicidal activity. For example, when 3-isothiazolones, such as 4,5-dichloro-2-n-octyl-3-isothiazolone, are included in the aqueous coating composition, it is desirable to include metal ion stabilizers to prolong the activity of the 3-isothiazolone component. However, metal ions are known to chemically degrade haloalkynyl microbicides and detract from the overall antimicrobial effectiveness of the formulation. For example, U.S. Pat. No. 5,916,930 discloses the use of a wide range of chelating agents as additives to alkyd compositions containing un-chelated transition metal ions and haloalkynyl compounds.
There is a need for stabilized aqueous compositions that provide the enhanced activity of antimicrobial agents, such as haloalkynyl microbicides, while at the same time tolerating the presence of metal ions, which otherwise would degrade the haloalkynyl active ingredient. The problem addressed by the present invention is to overcome stability deficiencies of antimicrobial formulations containing haloalkynyl microbicides in the presence of metal ions by providing aqueous compositions of haloalkynyl compounds in the presence of chelated metal ion.